Musannaf Ibn Abi Shayba 27:454

Sharīk narrated to us, from Abū Yazīd al-Awdī, from his father, who said: Abū Hurayrah entered the mosque, and we gathered around him. A young man stood up to him and said: "I adjure you by Allah, did you hear the Messenger of Allah (peace and blessings of Allah be upon him) say: 'Whomever I am his master (mawla), then ‘Alī is his master. O Allah, befriend whoever befriends him and be hostile to whoever is hostile to him'?" He said: "Yes." The young man said: "I am quit of you; I bear witness that you have been hostile to whoever he befriended and befriended whoever he was hostile to." He said: So the people pelted him with pebbles.